给定一个字符串,“”aabbcdeeeeggi“和k = 3,代码应该找到最长的子字符串,最多有k个唯一字符。对于上面的输入,它应该是”deeeeggi“。
Here是针对Python问题的优雅O(n)解决方案。我在Java中实现。但我没有得到所有输入的所需输出。
public class SubStringWithKUniqueCharacters {
public static void main(String[] args){
System.out.println(longestSubStringWithUniqueK("aabbcdeeeeggi", 3));
System.out.println(longestSubStringWithUniqueK("aabbcdeeeeggi", 2));
}
public static String longestSubStringWithUniqueK(String input, int k){
int len = input.length();
Set<Character> unique = new HashSet<>();
int i = 0;
int j = 0;
int count = 0;
int maxStartIndex = 0;
int maxEndIndex = 0;
int maxLen = 0;
char[] inputArr = input.toCharArray();
while (i<len){
if (count==k && j -i > maxLen){
maxStartIndex = i;
maxEndIndex = j;
maxLen = maxEndIndex - maxStartIndex;
}
if (count<k && j<len){
if (unique.add(inputArr[j])){
count++;
}
j++;
}
else {
if (unique.remove(inputArr[i])){
count--;
}
i++;
}
}
return input.substring(maxStartIndex,maxEndIndex);
}
}
这是输出:
eeeeggi //correct output
eeeggi //incorrect output
我无法捕捉到bug的位置。任何帮助将非常感激。 感谢
答案 0 :(得分:1)
你的实现没有像预期的那样工作,因为原来的python解决方案有bug。我对你的代码做了一些修改。希望现在好了:
public class SubStringWithKUniqueCharacters {
public static void main(String[] args){
System.out.println(longestSubStringWithUniqueK("aabbcdeeeeggi", 3));
System.out.println(longestSubStringWithUniqueK("aabbcdeeeeggi", 2));
}
public static String longestSubStringWithUniqueK(String input, int k){
int len = input.length();
Set<Character> unique = new HashSet<>();
int i = 0;
int j = 0;
int count = 0;
int maxStartIndex = 0;
int maxEndIndex = 0;
int maxLen = 0;
char[] inputArr = input.toCharArray();
while (i<len){
if (count==k && j -i > maxLen){
maxStartIndex = i;
maxEndIndex = j;
maxLen = maxEndIndex - maxStartIndex;
}
// 1. if we reach the end of the string, we're done.
if (j + 1 > len){
break;
}
// 2. changed to count <= k here
else if (count<= k && j<len){
if (unique.add(inputArr[j])){
count++;
}
j++;
}
else {
if (unique.remove(inputArr[i])){
// 3. remove all consecutive chars of the same value
char c = inputArr[i]; // save as temp char
while (inputArr[i] == c)
{
i++;
}
count--;
}
}
}
return input.substring(maxStartIndex,maxEndIndex);
}
}
现在的输出是:
deeeegg
eeeegg